Stacked semiconductor chip RGBZ sensor

Abstract

An apparatus is described that includes a first semiconductor chip having a first pixel array. The first pixel array has visible light sensitive pixels. The apparatus includes a second semiconductor chip having a second pixel array. The first semiconductor chip is stacked on the second semiconductor chip such that the second pixel array resides beneath the first pixel array. The second pixel array has IR light sensitive pixels for time-of-flight based depth detection.

The invention claimed is: 
     
       1. An apparatus, comprising:
 a first semiconductor chip having a first pixel array, said first pixel array having visible light sensitive pixels; and, 
 a second semiconductor chip having a second pixel array, said first semiconductor chip stacked on said second semiconductor chip such that said second pixel array resides beneath said first pixel array, said second pixel array having IR light sensitive pixels for time-of-flight based depth detection, wherein, an IR sensitive pixel resides directly beneath one or more of the visible light sensitive pixels such that incident IR light received by the IR sensitive pixel passes through the one or more visible light pixels, and wherein, a light guide structure resides directly beneath the one or more visible light pixels and between the one or more visible light pixels and the IR sensitive pixel, the light guide structure to receive the IR light that has passed through the one or more visible light pixels and direct the IR light to the IR sensitive pixel so that the IR sensitive pixel can respond to the IR light. 
 
     
     
       2. The apparatus of  claim 1  wherein said first semiconductor chip is thinner than said second semiconductor chip. 
     
     
       3. The apparatus of  claim 1  wherein said second semiconductor chip is stacked on a third semiconductor chip. 
     
     
       4. The apparatus of  claim 3  wherein said third semiconductor chip contains any of:
 pixel array circuitry coupled to said first pixel array; 
 pixel array circuitry coupled to said second pixel array; 
 ADC circuitry coupled to said first pixel array; 
 ADC circuitry coupled to said second pixel array; 
 timing and control circuitry coupled to said first pixel array; 
 timing and control circuitry coupled to said second pixel array. 
 
     
     
       5. The apparatus of  claim 1  wherein said first semiconductor chip contains any of:
 pixel array circuitry coupled to said first pixel array; 
 ADC circuitry coupled to said first pixel array; 
 timing and control circuitry coupled to said first pixel array. 
 
     
     
       6. The apparatus of  claim 1  wherein said second semiconductor chip contains any of:
 pixel array circuitry coupled to said second pixel array; 
 ADC circuitry coupled to said second pixel array; 
 timing and control circuitry coupled to said second pixel array. 
 
     
     
       7. The apparatus of  claim 1  wherein said second semiconductor chip is mounted on a package substrate. 
     
     
       8. The apparatus of  claim 1  wherein said first semiconductor chip contains through-substrate-vias. 
     
     
       9. The apparatus of  claim 1  further comprising a micro-lens array formed on said first semiconductor chip. 
     
     
       10. The apparatus of  claim 9  wherein said second semiconductor chip does not have a micro-lens array formed thereon. 
     
     
       11. A method, comprising:
 receiving visible light and IR light at a surface of a first pixel array; 
 sensing said visible light but not said IR light with one or more visible light pixels of said first pixel array, said IR light passing through said one or more visible light pixels of said first pixel array; 
 passing said IR light through a light guide structure located beneath said one or more visible light pixels; 
 sensing said IR light with an IR pixel of a second pixel array located beneath said light guide structure. 
 
     
     
       12. The method of  claim 11  wherein said sensing IR light further comprises sensing time-of-flight depth information. 
     
     
       13. The method of  claim 11  wherein said method further comprises running signals to/from said first pixel array through said second pixel array's semiconductor substrate. 
     
     
       14. The method of  claim 11  wherein said sensing said visible light and said sensing said IR light are performed simultaneously. 
     
     
       15. The method of  claim 11  further comprising performing analog-to-digital conversion and/or timing and control functions for either or both of said first and second pixel arrays with a semiconductor chip that said second pixel's semiconductor chip is stacked on. 
     
     
       16. An apparatus, comprising:
 an applications processor having a plurality of processing cores and a memory controller coupled to the plurality of processing cores; 
 a camera system coupled to the applications processor, said camera system comprising: 
 a first semiconductor chip having a first pixel array, said first pixel array having visible light sensitive pixels; and, 
 a second semiconductor chip having a second pixel array, said first semiconductor chip stacked on said second semiconductor chip such that said second pixel array resides beneath said first pixel array, said second pixel array having IR light sensitive pixels for time-of-flight based depth detection, wherein, an IR sensitive pixel resides directly beneath one or more of the visible light sensitive pixels such that incident IR light received by the IR sensitive pixel passes through the one or more visible light pixels, and wherein, a light guide structure resides directly beneath the one or more visible light pixels and between the one or more visible light pixels and the IR sensitive pixel, the light guide structure to receive the IR light that has passed through the one or more visible light pixels and direct the IR light to the IR sensitive pixel so that the IR sensitive pixel can respond to the IR light. 
 
     
     
       17. The apparatus of  claim 16  wherein said first semiconductor chip is thinner than said second semiconductor chip. 
     
     
       18. The apparatus of  claim 16  wherein said second semiconductor chip is stacked on a third semiconductor chip. 
     
     
       19. The apparatus of  claim 18  wherein said third semiconductor chip contains any of:
 pixel array circuitry coupled to said first pixel array; 
 pixel array circuitry coupled to said second pixel array; 
 ADC circuitry coupled to said first pixel array; 
 ADC circuitry coupled to said second pixel array; 
 timing and control circuitry coupled to said first pixel array; 
 timing and control circuitry coupled to said second pixel array. 
 
     
     
       20. The apparatus of  claim 18  wherein said first semiconductor chip contains any of:
 pixel array circuitry coupled to said first pixel array; 
 ADC circuitry coupled to said first pixel array; 
 timing and control circuitry coupled to said first pixel array. 
 
     
     
       21. The apparatus of  claim 18  wherein said second semiconductor chip contains any of:
 pixel array circuitry coupled to said second pixel array; 
 ADC circuitry coupled to said second pixel array; 
 timing and control circuitry coupled to said second pixel array.